Refillable fuse



Jam 14, 1930. 5G. K. ANDERSON ET A1. LMAW REFILLABLE FUSE Filed April 26, 1928 Patented Jan. i4, iesof maar@ .ERNST G. K. ANDERSON, AOF VNSTON, AND NILS A. TORNBLOM, OF CHICAGO, ILLINOXS, ASSIG-NORS T .APPLETON ELECTRIC COMEANY, A CORPORATION OIE' ILLINOIS BEFILLABLE FUSE Application filed April 26,

The ordinary reillable fuse of large capacity, in which the terminals are made 1n blade form, usually consists of numerous parts that must be assembled when a fuse is to be in- 5 serted or replaced. The device is theretore expensive to manufacture and inconvenient in use whenever a fuse must be replaced. vWhen a fuse is blown, one terminal of the device remains alive. In the ordinary fuse device construction care must be `taken in lifting the device out of the clips in order to replace the fuse, to prevent the hand from coming in contact with metal parts that may be connected to the live terminal.

The present inventionv has for its ob]ect to produce `a simple and novel reil'lable Jfuse that will befree from the objections above noted.

Viewed inv another aspect, thepresent invention may be said to have for its ob]ect to produce a rellable fuse device that shall consist of a minimum number of separable parts and that'shall have no portion of metal or other conducting material in position to come in contact with the hand when the device-1s grasped inthe'act of removing or replacing the device.

In carrying out our invention, we employ only two units, a core unit and a casing unit; the core unit consisting of a body of insulating material into which are molded terminals between which the fuse element is connected; and the casing member consisting o f a shell of insulating material adapted to be slipped over the core so as to leave only the terminal strips or bars projecting. The casing is preferably made in the form of a cylindrical shell having internal screwthreads at one end; -while the core is made of a'plug of insulating material having cylindrical ends one of which 1s provided with screwthreads to permit the core to be screwed into the cylindrical casing.; and the terminals passing into the ends of the core at the longitudinal axis of the latter. Between the cylindrical ends the core 1s shaped to receive the fuse element and to expose the inner ends of the terminals so as to permit the fuse element to be attached thereto.

Generally speaking, the present invention i928. sei-iai No. 272,926.

may be 4said to have for its object to simplify and improve the construction of fuses.

The various features of novelty whereby our invention is characterized will hereinafter be pointed out with particularity in the claims; but, for a full understanding of our invention and of its objects and advantages, reference may be had to the following detailed' 4description taken in connection with the accompanying drawing, wherein:

Figure l is a perspective view of a device arranged in accordance with our invention; Fig. 2 is a view showing the core unit in elevation and the casing unit in section; F 3 is a longitudinal central section through the device as a whole; Fig. 4 is a bottom view of the core unit; Figs. 5 and 6 are sections taken respectively on lines 5 5 and 6-6 0f Fig. 2; and Fig. 7 is a view of the right hand end of the core unit as it appears in Fig. 4.

Referring to the drawing, 1 represents a 'long body of insulating material generally cylindrical in form and of slightly enlarged diameter at the ends The enlarged section 2 at one end is smooth on the exterior while the enlarged section 3 at the other end lis screwthreaded. Outwardly beyond the screwthreaded portion is a flange or head 4 of Greater diameter than the screwthreads.

'lerminals 5 and 6,' lying beyond the two ends of the member lliave Shanks extending into the latter; the terminals lying at the longitudinal axis of the memberA 1. The member l, that vis the body member, and the terminals are preferably united by molding the body member about the shank ends of the terminals. The body member is cut away on one side between the enlarged end sections to a depth to expose the inner ends of the shank portions of the terminals. The area `between the inner ends of the terminal pieces is hollowed out toproduce a trough 7. What may be termed the top edge of one of the side walls of the trough 7, indicated at 8, lies in the same plane as the top faces of the at terminal reces.v The other side wall of the trough, indicated at 9, extends a considerable distance above the plane of the tops of the terminal pieces so as to form a ledge along one side of the latter.

The inner end of the shank of each 106 terminal piece is provided with a h ole 10 to receive a screw 11. The two termmals are connected by a fuse strip l2 extending between and overlylng the exposed inner ends of the.

Shanks of the terminal pieces and held thereto by means of the screws. The fuse strip 12 has the usual slots 13 extending into the same, past the middle, from one edge, so that the strip may be engaged with thescrews by moving it laterally, with the slots registering with the stems of the screws after the screws have been loosened.

Cooperating with the core unit is a casing in the form of a cylindrical shell 14 having an interior bore of the same diameter as the diameter of the smooth end section 2 on the member 1. One end of the shell is screwthreaded on the interior to receive the screwthreaded part 3 Yof the core member. When the core is inserted in the casing, smooth end first, and is then screwed in, the flange 4 willv abut against one end of the casing and form astop to limit the relative endwise movements of the core and casing.

When a fuse blows, the hot gases should be permitted to escape so as not to destroy the casing. To this end we place one or more zigzag grooves 1,5 across the thickened end 2 of the body member 1; these Grooves being on what may be termed the bac or bottom side, namely on the side opposite that in which the fuse strip is located. Because of the enlarged ends or the body member of the core, there will be a narrow annular space between the casing and the maj or portion or" the core monrber. When a Jinse blows, the gases enter' this space from which the air may `escape through the zigzag passages. After the air llas been :forced out, the combustion gases may ollow, provided there still remains a pressure in the interior of the device. By mahmgthe grooves small in cross-section and of .zigzag shape, a

resistance to the escape of gases is presented.

lt will thus be seen that our improved device, including the terminals, consists of'two main pieces or units, only the two screws and the fuse strip being required to complete the same,I When a fuse is to be replaced, the device may be grasped in the hand to detach it trom the clips in which the terminal blades are secured, without danger of coming in contact with any exposed metal art. .Alfter the device has been detached, t' e casing or shell is unscrewed and slipped ed and, upon loosening the screws, a new fuse strip ma be slipped in and the screws again tightene 'lhe structure as a wholeis therefore simple,v

ma be handled safely, and permits a inse stri to be replaced easily and conveniently wit out danger of loosening or mislaying any essential art.

lewe ave illustrated and described with particularity only a single preferred form of our invention, we do not desire to be limited to the exact structurel details thus andere illustrated and described; but intend to cover all forms and arrangements which come within the deinitions of our invention constituting the appended claims.

We-claim z- 1. A refillable kfuse comprising a cylindrical open-ended shell of insulating material having an internal screwthread in one end, a core element of insulating material having at une end a screwthread complementary to that in the shell and having outwardly beyond the screwthreadsa flan e to engage with the end of the shell, the main portion of the core element being slightly smaller in diameter than the interior of the shell to leave an annular space between the same and the shell, terminals fixed in the ends of the core element and projecting outwardly therefrom, one side of the core element being cut away on a plane approximately flush with corresponding faces on the inner ends of the terminals and exposing such inner ends, and a fuse strip extending between and overlying the inner ends of said terminals, said fuse strip having slots extending into the same from the same edge near the two ends, and the inner ends of the terminals having screws spaced apart a distance equal to the distance between said slots, to permit the fuse strip to be inserted by moving it laterally.

2. A rellable l*fuse comprising an open- ,ended shell of insulating material having an internal screwthread, a core element or insulating material screwedinto said shell, said core element having a recess in the side and at some distance from each end, terminals moulded in the core element and each extending from the recess through one end of the core element, and a fuse det-achably secured between the inner ends of the terminals,

3. A reillable fuse comprising a tubular4 shell or insulating material internally screwthreaded at one end, a cylindrical core element of insulating material having at one end a dange' and screwthreads inwardl oit Athe dange to lit the screwthreads in theshell, the core element being reduced in diameter throughout except toward the ends and being cut away on one side to form e recess, terminals moulded into the ends of the core element and extending from said recess through the ends, a fuse strip between the inner ends of said terminals, and there being a tortuous-pas sage to one end of said element on the side op= posite that on which the recess lies.

lin testimony whereof, we sign this specication. .v A- j i ERNST G. K. ANDERSGN. N il..4 "l"RhTBlJlOUl/l.v 

